Rear end Vibration between 3-4k rpm

[ukrainekid]

Ok so I recently swapped my KA to an SR. The SR is running beautifully expect for one thing. When I am on the throttle, not necessarily full throttle but being generous, I get this weird vibration in the rear end between 3-4k rpm. It feels almost like wheel hop but not that really pronounced wheel hop when burn out and have bad rear sub frame bushings. Maybe you guys can give me some ideas. I'm hoping its the sub frame bushings and nothing else more complicated.

Car specs;
-S-chassis 248k miles
-No suspension work expect for some Megan Coilovers

Here is a pic of my freshly swapped engine

[mechanicalmoron]

Is it in every gear?

Maybe check that motor, transmission, and differential mounts are all tight.

And maybe make sure that your driveshaft carrier bearing/u-joint/balance is okay.

You can eleminate the actual rear end (or the front, depending on the result) by checking neutral. If it happens when you race the engine in neutral when you're parked, then it's in the motor/transmission or their mounts, and if it only happens when you're driving and in gear, then it's between the rear of the transmission and the wheels.

I guess it could POSSIBLY be a bearing or something in the transmission and break my example, but it would be less likely I think.

[drifteds14]

Mounts maybe, add suspension , dont ebay it

[nightheron]

First thing that I'd do is make sure that the tires are balanced and that the wheels are true and don't wobble while spinning on the balancer.

[ukrainekid]

Is it in every gear?

Maybe check that motor, transmission, and differential mounts are all tight.

And maybe make sure that your driveshaft carrier bearing/u-joint/balance is okay.

You can eleminate the actual rear end (or the front, depending on the result) by checking neutral. If it happens when you race the engine in neutral when you're parked, then it's in the motor/transmission or their mounts, and if it only happens when you're driving and in gear, then it's between the rear of the transmission and the wheels.

I guess it could POSSIBLY be a bearing or something in the transmission and break my example, but it would be less likely I think.

Sorry everyone I was on Vaca and i neglected to get online lol. . FYI..car had been recently aligned with 4 brand new tires

Ok so I installed energy subframe bushings and the weird vibration between 3k-4k rpm is gone. Now on the other hand a new noise has begun in the rear. The new noise comes when I shift and it sounds like a "clunk" type of noise like if something was loose back there but I double checkes all bolts and everything is tight like tiger. Can this possibly be my Differential bushing making noise now that I have really solid subframe bushings??? if its not one thing, its the other lol....

[Ullusion]

I too have an occasional vibration from the rear of my vehicle when in gear and I'm going down a bumpy road. Sometimes I feel it on smooth roadways as well under sudden acceleration. Hopefully its not the rear end. I plan on doing a drain and refill of the diff and checking everything again and make sure nothings loose..Probably would help to notate if you marked your driveshaft-to-diff position during your swap. Its good to do so because reinstalling it the way it came off will ensure a properly balanced drive shaft in relation to the diff.